U.S. Pat. No. 4,749,404 describes herbicidal liquid concentrate compositions of salts of 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-3-quinolinecarboxylic acid which may be combined with an organic dinitroaniline composition and U.S. Pat. No. 4,822,405 describes concentrated oil in water emulsion combination compositions of water soluble salts of imidazolinone herbicides and dinitroaniline herbicides. However, the ratio of herbicides which may be employed is limited because of problems with crystallization which may occur with more concentrated formulations especially when storing the compositions at low temperatures. In addition, these compositions employ salts of imidazolinones and require both aqueous and organic solvents.
Pending application for U.S. Letters, Patent Ser. No. 440,179, filed on Nov. 22, 1989 (abandoned) describes herbicidal emulsifiable suspension concentrate compositions which contain an active herbicidal agent or combination of agents. However, suspension compositions are not entirely satisfactory because crystallization of the active herbicidal agent, upon extended storage at low temperature, is enhanced by the solid active herbicide present in the suspension.
It is therefore an object of the present invention to advantageously provide an emulsifiable concentrate combination composition in which all of the active herbicidal agents are dissolved in a single solvent which may be stored at lower temperatures and for a longer period of time than suspension concentrate compositions or concentrated oil in water emulsion compositions.
It is also an object of the present invention to provide herbicidal emulsifiable concentrate compositions of free acids of imidazolinone herbicides and 2,6-dinitroaniline herbicides which are physically and chemically stable.